Circuit breakers for panelboards



A. R. NORDEN CIRCUIT BREAKERS FOR PANELBOARDS Filed Feb. 26, 1958 BY j;

ATTORNEY United States Patent Filed Feb. 26, 1958, Ser. No. 717,647 4Claims. (Cl. 200-116) The present invention relates to circuit breakers,especially for mounting on standard circuit breaker panelboards.

Circuit breaker panelboardis, particularly the plug-in type such as thatof the type disclosed in U.S. Patent 2,647,225, issued July 28, 1953 toT. M. Cole et al., have 'gained great popularity and are in widespreaduse. This success in part may be attributed to the fact that both thepanelboard and the circuit breakers are manufactured as standard items,the circuit breakers being supplied in a variety of ratings (to amaximum) to be selected and mounted on the panelboard as required byeach particular installation and Without requiring any individualattention by the manufacturer to the particular job. The standardizedcircuit breakers for each manufacturers panelboard have the samephysical proportions (per pole) regardless of rating, up to a maximum,and the {panelboard is designed to operate according to establishedsafety standards when fully equipped with the standard circuit breakers.

An object :of the present invention is to provide a novel form ofcircuit breaker having a heavier per-pole current rating than themaximum standard circuit breakers available for use with thestandardized panelboards, without however interfering with theversatility or flexibility of the standardized panelboards or with theirmeeting established standards. Previous standard circuit breakers andthe novel circuit breakers can be used in accordance with jobrequirements Without r y special attention by the manufacturer to eachjob requirement.

Panelboards for circuit breakers are commonly designed to be energizedfrom diderent phases of an alternating current supply. Wherecenter-tapped single phase service is furnished, the centerv tap isarranged as a neutrai land the two outside wires of the supply arereferred to as phases; and this term is also used to designate theseparate supply lines of a three-phase power supply for which otherstandard panelboard-s are designed. Both single-phase and three-phasepanelboards are sequencephased, that is, the bus terminals of bothclasses of panelboards are subdivided, adjacent portions of thesubdivided bus terminal assembly being adapted for connection to thedifferent phases of the supply. The adjacent poles of multiple circuitbreakers mounted at a subdivision of the bus can then be energized bydifferent phases of the supply. According to a further feature of theinvention, a novel multipole circuit breaker is provided for mounting ona standard sequence-phased panelboard where the rating of the individualpoles of the multipole circuit breaker is heavier than the maximum safestandard individual pole rating for which :the panelboard is intended,While at the same time insuring approved operation of the panelboardaccording to established standards.

The nature of the invention and further features of novelty and otheraspects of the invention will be better appreciated from the following`detailed description of an Patented Feb. 4, 1964 illustrativeembodiment thereof, shown in the accompanying drawings forming part ofthe disclosure of the invention. In the drawings:

FIG. 1 is the plan view of a circuit breaker panelboard of standarddesign, bearing circuit breakers of standard design together with anillustrative form of a two-pole circuit breaker embodying features ofthe present invention; `and FIG. 2 is an enlarged cross-section of theapparatus in FIG. 1 taken along the line !2-2.

A panel assembly is shown in FIGURES l and 2 of the type in theaforementioned Cole et al. patent. This panel-'board is of a form toreceive rtwo rows of single pole circuit breakers with four single-'polecircuit breakers in each row; or, alternatively, the standard panelboardis adapted to receive one two-pole circuit breaker in each row and,additionally, two single pole circuit breakers in each row. Two-polecircuit breakers suitable for use here may be of the .type in the`Christensen et al. P-atent 2,662,949 issued December 15, 1953. Two-polecircuit breakers are characterized by having two circuits that areentirely electrically separate :and which are commonly designated polesEach pole includes a line termina-l, a load terminal, la pair ofcontacts which are closed and opened to make and break the circuit fromthe supply terminal to the load terminal, and an overload releaseelement. The poles of .a two-pole circuit breaker have a commonoperating handle and each pole may have itS separate operatingmechanism, or a single contact-operatin-g mechanism may be provided forall of the poles. The overload release means of each pole in any casecauses automatic opening of the contacts of the several poles upondetection 'of yan overload in any one pole. lWhile the 'discussion ofpoles above refers to singleand twopole circuit breakers, it is fullyapplicable to three-pole circuit breakers.

The panelboard in FIGS. l and 2 is designed for the usual three-wiresingle phase power distribution system. A three-phase sequence-'bussedpanelboard such as that in my Patent No. 2,739,272 issued March 20, 1956will naturally be used with the three-prole circuit breaker.

The illustrative panelboard for receiving the circuit breakers includesa terminal pan assembly comprising a mounting pan 10 having a series ofintegral hooks 12 at the lateral edges as viewed in FIG. 1. A terminalassembly generally designated 14 includes a member 16 of moldedinsulation having a downward projection 18 that fits into acorresponding hole in pan 10i and lateral projections 20 that areengaged by overhanging lances 22 integral with pan 10. Lances 22 preventthe molded linember 16 #from being lifted away from fthe pan, andprojection 18 of member 16 prevents the molded member from slidinglengthwise out of engagement with retaining lances 22.

Insulating member 16 supports a pair of lterminal members 24 and 26,which are designed to be connected as by screw `connectors 28 and 30 tothe two outside legs or phases of a three-Wire single phase alternatingcurrent power line. Terminal members 24 and 26 are secured to insulatingmember 16 by screws 32 that extend from the bottom of the molded member16 up into respective threaded openings in the members 24 and 26.Further, each terminal member 24 and 26 includes a series orf formations34 which constitute individual bus terminal formations ycomplementary tothe individual terminals of the circuit breakers mounted by the mountingpan and terminal assembly. In the embodiment shown in the drawings, theformations 34 are in the form of slots which receive male plug-interminals of the illustrative circuit breakers; but in another widelyused form of plug-in circuit breaker, the terminal formations of thepanelbo-ard are male members or blades that are complementary toresilient metal clips constituting the plug-in 4terminals of the circuitbreakers. Such male panelboard terminal formations or blades .may bedisposed in the same direction as the slots 34 or they .may extendacross the terminal assembly 14, at right angles to the shown elongatedslots 34 that they 4would replace.

One retaining hook 12 and one formation 34 are provided for cooperatingwith each pole olf the circuit breakers mounted by the mounting pan andterminal assembly shown. In the illustration, pan provides two rows ofcircuitbreaker receiving areas 10A at opposite sidesV ofthe terminalassembly 14, four. such areas being shown on each side of the terminalassembly.

A pair 'of single-pole circuit breakers 36 appear in the bottom areas10A in the two rows of circuit breaker receiving tareas. The terminalformations 34 that cooperatewith the male plug-in terminals (not shown)of those bottom two circuit breakers 36 are both in one portion 38 ofthe:terminal member 36, inasmuch as the bottom two circuit .breakers -36are properly connected to the same phase. A-pair of terminal formations34 are similarly available =for mating with the plug-in terminals of thetop pair of circuit breakers 36 in FIG. l at opposite sides of the.terminal assembly l14. Terminal members 24 and 26 embody additionalportions 42 and 44 respectively for respective poles of circuit breakersatopposite sides of the terminal assembly 14.

Terminal portions 42 and'44 are of `different phases, and they areadjacent each other, so that a twodpole circuit vbreake-r yhaving a pairof stab plug-in terminals, of the form in the Christensen et al. p-atentmentioned above, can be mounted in either the left-hand row or therighthand rowsof areas 10A of the mounting pan; and each of ythe polesof the two-pole circuit breaker thus mounted would be connected torespectively diiferentphases. At this point/the terminals of thepanelboard are said to be sequence-phased; vIt is evident that theterminals :provided bythe terminal assembly 14`could be 100% sequence.

phased, by connecting areas 40, 42, 44 and 38 to the alternate supplyphases, and in that event a two-pole circuit breaker of convention-alform could be mounted at any point on the panelboard. However, it isapparent thaty whether the-limited sequence-phasing of the bus terminalsZ4Jand 26 as illustrated is employed or whether 100% sequence phasing ofthe terminal portions 38, .40,42 and 44 y is used, the terminalform-ations 34 associated with each opposite pair of poles 36 in tworows of areas 10A are .connected to the same phase. A 100%sequencephased panelboard construction is shown in my patent mentionedabove. That panelboard has two rows of circuit breaker receiving areas10A, and there as here the pairs of opposite poles (one pole in eachrow) are counected to the same phase bus.

The load or current capacity for which the panelboard and terminalassembly of FIG. 1 may be rated depends to a large extent on the currentcarrying capacity of the bus terminals provided. Correspondingly, thebus terminals must be of sufficient capacity to accommodate the fullcomplement of circuit breakers 36, within the standard, range kofratings of circuit breakers of that outline. Thus, the terminal assemblyillustrated as well as the entire mounting pan and terminal assemblyillustrated may be rated for i100 amperes to accommodate a typicalcomplement of circuit breakers 36 whose ratings may be any combinationof values between 15 and 50 amperes.

In accordance with features of the present invention,

circuit breakers 46 are provided for heavy currents having enclosuresproportioned to be mounted on thel standard mounting pan assemblyillustrated, without however exceeding the rating of the panelboard. Thenovel twopole circuit breaker illustrated includes one pair of male orstab terminals 48 of one pole thereof that mate with portion 42 ofterminal member 24, and a similar pair of stab terminals 48 are providedfor the other pole of the circuit breaker, to mate with terminal portion44 of the bus assembly. In this way, the standard pane-lboard canreceive a two-pole circuit breaker at one side of the terminal assembly14, in the space provided for two single poles; and this circuit breakermay be rated at amperes, for example, without danger of overloading thepanelboard.y The heavy-current circuit breaker 46` engages not only theterminal formations 34 associated with the circuit breaker receivingareas A10A in the row which it `occupies but also the terminalformations 34 associated with the circuit breaker receiving areas 10A inthe other row, at the opposite side of the terminal assembly 14. Eachpole o-f the novel circuit breaker 46 with its dual plug-in terminalfully. occupies an area 10A and additionally preempts part of theopposite circuit breaker receiving area 10A of the opposite row ofcircuit breaker receiving areas 10A. This prevents mounting of a circuitbreaker or a pair of circuit breaker poles in those areas 10A in the rowopposite that where the circuit breaker has been mounted. It is evidentalso that the dual circuit breaker plug-in terminal 48 hasproportionately greater contact surface engaging the te-rminal 14, andtwice the current-carrying capacity or a single circuit breaker stabthat engages a single slot 34, and the multiple circuit breaker retainsthe side-by-side varrangement of coordinated poles and may be 4mountedtoengagethe respectively different phases of the panelboard busassembly.

One of the poles of circuit breaker 36 is shown in FIG. 2 in broken-awaycross-section. screw connector 50 is shown at the end of the enclosure52 of molded insulation remote from dual terminal 48; and this screwterminal 50 is joinedl by metal braid .51

to a resiliently. mounted contact 54. Spring 55l biasescontact 54downward in the illustration. When the companion movable contact 56 isremoved, the travel of the contact 54 is limitedby shoulders 58 formed`integrally in the molded enclosure 52.y f

Contact 56 is carried by a movable arm 59 as of copper to which there isunited a current responsive bimetalH have lateral formations that areloosely complementary to formations in the molded insulating enclosure52 and are accordingly movable flexibly in relation to each other. A rodof insulation 69 projects integrallyl from the wall of enclosure 52 tospace stabs 48 and `promote alignment with respective slots-34.H In'this way, each stab'. can shift individually into proper plug-incontact'engage-` ment with terminal member24 (FIG.'2).

A furtherfea-ture `contributing to the successful heavy currentoperation of the disclosed circuit breakerwhich is basically of the samesmall enclosure outline as the pre-V vrous `circuit breakers resides inthe mounting of contact 54 in relation to the companion contact 56 andits operating means. The operating linkage for 'contact arm 59- is madeup of rigid elements, so that pressure. of 'contact 56 against contact54 is built up against springSS.

As the moving contact 56 swings-down in the drawing, f

Contact 54 follows under tirm spring bias. Its travel is interrupted byshoulders `58. Inasmuch as shoulder 58 l In that view, a-

at the right is higher than the other shoulder, the righthand yedge ofthe contacts part lfirst, .the spring maintaining the left-hand portionlof contact 54 in engagement with contact 56. The parting of thecontacts then starts arcing at the ileft, and the arc blows out towardthe left, all of which acts to minimize the damage Ito the contactsresulting from opening the contacts under load and particularly whencarrying short-circuit current.

Closing of the contacts operates in reverse, the initial contact firstoccurring at the left-hand portion of the contacts and then shifting lbya rocking or tilting of contact 54 until face contact is made. Thisaction insures that that portion of the contact surfaces that have beenleast abused inthe contact-making and breaking operations will carry theoperating current, resulting in cooler operation and lower contactresistance.

Each pole of the circuit breaker 46 includes the elements shown in FIG.2. Inasmuch as the mechanism causing two-pole operation, that is,simultaneous opening of the contacts in response to a single-poleoverload, forms no part of the present invention, little purposeapparently would be served by burdening the present specication withfurther details thereof. A single operating handle 66 for thecoordinated side-by-s-ide poles is shown in FIG. 1.

Circuit breaker panellb'oards normally include 1a trim plate whichcovers up the wiring and presents a neat finished appearance of theentire assembly. Trim plate 70 of standard design as shown in FIG. 2 hasa hole 72 formed therein for accommodating the handle 66 of the circuitbreaker 46, together with a protruding portion of the circuit Ibreakerenclosure 52 that surrounds the operating handle. Trim plate 70 normallyhas a series of knockouts formed in the various places where the circuitbreakers may project. However, inasmuch as the panelboard may [be onlypartly iilled with circuit breakers, these knockouts are left intact asparts of the trim plate in those areas Where circuit breakers are notinstalled. In the case of the circuit breaker illfustrated, whichpreempts the terminal portion-s 34 associated with both the righthandand .the left-hand rows of circuit breaker receiving areas A, as slrownin FIG. l, the knockouts in trim plate 70 (at the right-hand side of theplate as viewed in FIG. 2) are lleft intact. The trim plate thus coversthe areas 10A which are necessarily left empty because of the specialconstruction of circuit breaker 46 which prevents additional circuitl'breakers from being received therem.

The circuit breaker enclosures 5'2 have a relief or cutout 53 in theirotherwise lgenerally rectangular outline, which accommodates theterminal bus iasse-mbly 14- while at the same time allowing the circuitbreaker enclosures 52 to rest iixush against the mounting pan :10k

When a circuit breaker is to be installed, the circuit breaker is movedinto engagement with one of the hooks 12 i-tting into a recess 57 in theenclosure 52, the parts 12 and 57 functioning as a separable hinge tolocate the circuit breaker both right-to-left in FIG. 2 andperpendicular to the View, so that the stabs 48- can be driven directlyinto slots 34. Trim plate 70 is lassembled to the position in FIG. 2after all the required circuit breakers have been mounted.

The circuit breaker y46 may obviously be used to energize a branchcircuit which is thereby protected by the circuit breaker. However,particularly in panelborards having space for receiving a larger numberof circuit breaker poles, the wires '74 shown connected to the screwterminals 50 of circuit breaker 46 might very well be the power supplyline, circuit breaker '46 then serving as a main circuit breaker withthe remainder of the circuit breakers on the panelboard then serving forbranch-circuit protection.

While the embodiment illustrated and described above represents thepresently preferred form of the invention, it is evident that yit isnaturally subject to a wide variety of modiiication in detail las *wellas varied application Consequently the invention should be broadlyconstrued, consistent with its full spirit and scope.

What is claimed is:

1. A circuit breaker for mounting on a standardized panelboard of thetype having two confronting rows of modular circuit-breaker receivingareas and an elongated sequence-phased bus terminal assembly betweensaid two rows of areas, each modular circuit-breaker receiving areabeing elongated and extending perpendicular to the elongated busterminal assembly and the bus terminal assembly including individual busterminals that are sequencephased along the bus assembly, each suchcircuit breaker receiving area having an individual bus terminal adaptedfor engagement with the bus terminal of a pole of a circuit breakermounted therein, said circuit breaker having an elongated pole to occupyone of said circuit breaker receiving areas and including an enclosurehaving bus terminal means at one end thereof, a pair of separablecontacts, one of said contacts being connected-to said bus terminalmeans, and an overload responsive element, connected to one of saidcontacts, the bus terminal means of said elongated pole including onediscrete terminal formation disposed for engagement with the busterminal of said one circuit breaker receiving area and said busterminal means of said pole having an additional discrete terminalformation solidly connected to said one discrete terminal formation anddisplaced from said one discrete terminal formation along the elongatedpole and disposed to occupy and engage the individual bus terminalcorresponding to the confronting circuit breaker receiving area in theother row of such areas and thereby to prevent mounting of anothercircuit breaker in that confronting circuit breaker receiving area.

2. A multiple circuit breaker for plug-in mounting on a standardizedpanelboard of the type having two confronting rows of elongated modularareas for mounting single-pole and multipole circuit breakersside-by-side and having an elongated sequence-phased bus assemblybetween said two rows of modular areas, the sequencephased type of busassembly having a bus terminal in each modular area cooperable with anindividual circuitbreaker terminal formation and the bus terminals beingsequence-phased along the bus assembly, said multipole circuit breakerhaving a pair of side-by-side elongated poles to occupy two side-by-sidemodular circuit-breaker receiving areas of one row of panelboard areas,each pole of the multipole circuit breaker having a pair of separablecontacts, an overload responsive element connected to one of saidcontacts and bus terminal contact means connected to one of saidcontacts, the latter including one discrete terminal formation disposedfor engagement with the bus terminal of one modular circuitbreakerreceiving area and said bus terminal contact means of each pole of thecircuit breaker having an additional discrete terminal formation solidlyconnected to said one discrete contact portion and displaced from saidone terminal formation along the elongated pole and disposed to occupyand engage the bus terminal of the confronting circuit-breaker receivingarea in the other row of such modular panelboard areas and thereby toprevent mounting of another circuit breaker in that confronting circuitbreaker receiving area.

3. A circuit breaker in accordance with claim 2 for mounting on astandardized panelboard as aforesaid in which the individual busterminals lare of the plug-in type, further characterized in that -saiddiscrete terminal formations of the circuit breaker are plug-interminals cooperable with the individual bus terminals of the busterminal assembly of the panelboard.

4. A circuit breaker in accordance with claim 2 for mounting on astandardized panelboard as aforesaid in which the individual busterminals are of the plug-in type, further characterized in that saidone discrete terminal formation and said additional discrete terminalformation 7 8 are of the plug-in type, and -Wherein all of said one dis-2,647,225 Cole et al July 28, 1953 cretefterminalformations'offthernultipole` circuit breaker 2,712,580` Nickell `et al.Y Y l Julyl 5, v1955 are alignedtransverse tosaid 'side-by-sideelongated poles 2,810,048 Christensen Oct, 15,1957 and all of saidadditionaldiscrete"ter'rninal formations of 2,815,420 Moyerl Dec;-3,19757'- the rnultipole circuit breaker are aligned transverse to said 52,828,388v Christensen et al. 1 Mar.V 25, 195.8 Sideby-sideelongatedpoles.l 2,883,586 l Christensen f Apr; 21`-,l1959`fr 2,923,7951" Feb;`2, 1960@ References Cited in the'ifle of this'paten't 2,942,157 juneghl1960,41

UNITED STATES PATENTS 2,997,628 StL-'Johninr Ag. 28, 1961- 2,647,187Cole July'28, 1953 10

1. A CIRCUIT BREAKER FOR MOUNTING ON A STANDARDIZED PANELBOARD OF THETYPE HAVING TWO CONFRONTING ROWS OF MODULAR CIRCUIT-BREAKER RECEIVINGAREAS AND AN ELONGATED SEQUENCE-PHASED BUS TERMINAL ASSEMBLY BETWEENSAID TWO ROWS OF AREAS, EACH MODULAR CIRCUIT-BREAKER RECEIVING AREABEING ELONGATED AND EXTENDING PERPENDICULAR TO THE ELONGATED BUSTERMINAL ASSEMBLY AND THE BUS TERMINAL ASSEMBLY INCLUDING INDIVIDUAL BUSTERMINALS THAT ARE SEQUENCEPHASED ALONG THE BUS ASSEMBLY, EACH SUCHCIRCUIT BREAKER RECEIVING AREA HAVING AN INDIVIDUAL BUS TERMINAL ADAPTEDFOR ENGAGEMENT WITH THE BUS TERMINAL OF A POLE OF A CIRCUIT BREAKERMOUNTED THEREIN, SAID CIRCUIT BREAKER HAVING AN ELONGATED POLE TO OCCUPYONE OF SAID CIRCUIT BREAKER RECEIVING AREAS AND INCLUDING AN ENCLOSUREHAVING BUS TERMINAL MEANS AT ONE END THEREOF, A PAIR OF SEPARABLECONTACTS, ONE OF SAID CONTACTS BEING CONNECTED TO SAID BUS TERMINALMEANS, AND AN OVERLOAD RESPONSIVE ELEMENT, CONNECTED TO ONE OF SAIDCONTACTS, THE BUS TERMINAL MEANS OF SAID ELONGATED POLE INCLUDING ONEDISCRETE TERMINAL FORMATION DISPOSED FOR ENGAGEMENT WITH THE BUSTTERMINAL OF SAID ONE CIRCUIT BREAKER RECEIVING AREA AND SAID BUSTERMINAL MEANS OF SAID POLE HAVING AN ADDITIONAL DISCRETE TERMINALFORMATION SOLIDLY CONNECTED TO SAID ONE DISCRETE TERMINAL FORMATION ANDDISPLACED FROM SAID ONE DISCRETE TERMINAL FORMATION ALONG THE ELONGATEDPOLE AND DISPOSED TO OCCUPY AND ENGAGE THE INDIVIDUAL BUS TERMINALCORRESPONDING TO THE CONFRONTING CIRCUIT BREAKER RECEIVING AREA IN THEOTHER ROW OF SUCH AREAS AND THEREBY TO PREVENT MOUNTING OF ANOTHERCIRCUIT BREAKER IN THAT CONFRONTING CIRCUIT BREAKER RECEIVING AREA.